Genuine reviews are the cornerstone of our global community. You can only review travelers for which you organized an experience. You will be asked to review the traveler after the experience has taken place. By reporting your experience you will help other hosts to judge if they want to accept a reservation request from that traveler.
Login to your account > Click on your profile picture > Click on 'My Reservations' > Click on 'List'. You now see a list of all the experiences travelers booked with you. To review a traveler you click on the blue arrow (below 'Actions') of the booking/traveler you want to review. When you're done you click on 'Review Traveler' so that the review is saved and uploaded.
In addition to written reviews, you can also submit a star rating. The number of stars displayed on a listing page is an aggregate of the scores that different hosts have given to that traveler.